1 Introduction
1.1 Wide application of rubber products in modern life
Rubber is a crucial industrial substance that is utilized extensively in contemporary life. Rubber goods are ubiquitous and an essential aspect of our everyday existence, ranging from automobile tires to construction seals, daily essentials to medical apparatus. Rubber materials’ exceptional mechanical qualities, resilience to weathering, resistance to wear, and other qualities make them an essential component of both daily life and industry.
There are many uses for rubber goods, such as:
- Tires used in the transportation industry include those for cars, motorcycles, airplanes, etc.
- Construction: pipelines, gaskets, vibration-absorbing pads, etc.
- Mechanical field: buffer pads, several types of sealing rings, etc.
- Electrical and electronic fields: components for home appliances, insulating layers for wires and cables, etc.
- Medical and healthcare field: tourniquets, gloves, catheters, etc.
- Daily essentials: toys, athletic equipment, insoles, etc.
1.2 The importance of production and preparation technology to the performance of rubber products
Rubber goods’ preparation and production methods have a significant impact on their quality and performance. Rubber’s wear resistance, heat resistance, mechanical qualities, and other attributes are significantly influenced by various production methods.
2. Rubber materials and their properties
2.1 Chemical composition and molecular structure of rubber
Rubber is a polymer substance that can be natural or artificial, mostly made of hydrogen and carbon. Isoprene molecules, which create long-chain polymer structures through polymerization processes, are the fundamental building blocks of rubber.
Cis-1,4-polyisoprene is the primary component of latex released by rubber trees, which is used to make natural rubber. There are several varieties of synthetic rubber, including silicone rubber, styrene-butadiene rubber, and chloroprene rubber, which are created by chemical synthesis.
Rubber’s molecular chain has many double bond configurations, which contribute to its excellent elasticity and stretchability. Rubber molecules may create a cross-linked network structure by procedures like vulcanization, which improves the material’s mechanical qualities even further.
2.2 Characteristics and application fields of different types of rubber materials
Rubber materials are classified into two groups based on their chemical composition and performance attributes: natural rubber and different types of synthetic rubber.
Natural rubber is widely utilized in tires, rubber goods, and other industries because of its exceptional flexibility, heat resistance, and wear resistance.
Depending on the needs of the application, synthetic rubber comes in a variety of forms, including FKM rubber, styrene-butadiene rubber, and chloroprene rubber. They are employed in machinery, construction, electrical appliances, and other sectors. They have varying chemical resistance, heat resistance, cold resistance, and other qualities.
2.3 Mechanical, thermal, electrical and other performance indicators of rubber
mechanical characteristics, such as elastic modulus, tensile strength, and rip strength.
Thermal characteristics include thermal aging, thermal stability, thermal expansion coefficient, and so on.
Electrical characteristics include breakdown voltage, resistivity, and dielectric constant.
Chemical characteristics, such as resilience to weather, chemicals, and oils.
The performance and suitability of rubber materials in a range of application domains are directly determined by these performance parameters. To produce high-performance rubber products that satisfy application criteria, engineers must choose the right rubber materials and optimize their manufacturing methods depending on particular application needs.
3. Overview of rubber product production process
3.1 Formula design and batching process
The formulation and ingredient selection process is the initial stage in the manufacturing of rubber goods. This entails figuring out the kind and quantity of additives in addition to the kind and percentage of rubber base components. Sulfur, accelerators, antioxidants, fillers, and other substances are examples of additives that are used to enhance rubber’s mechanical qualities, weather resistance, and resistance to heat.
Formula design must be refined in accordance with the needs of a certain product’s use and then confirmed through experimentation. To guarantee correct proportions throughout the batching process, exact measurement and feeding techniques are needed.
3.2 Mixing process
The process of thoroughly combining and distributing the different additives with the rubber base material is called mixing. By taking this process, the rubber material may get high fluidity and plasticity, which will prepare it for further molding.
Open mixers, internal mixers, and other mixers are frequently employed. Rubber material performance may be enhanced and the mixing impact maximized by adjusting process variables like temperature and rotation speed.
3.3 Molding process (such as extrusion, calendering, injection molding, etc.)
The rubber material must be combined and then molded using a variety of techniques to give it the required product shape. The most common forms of molding are injection, calendar, and extrusion molding, among others.
Different molding techniques may be used to create rubber goods with a variety of sizes and forms, including tires, pipes, films, etc. To guarantee product quality, process parameters must be precisely controlled.
3.4 Vulcanization process
A crucial stage in the creation of rubber goods is vulcanization. Rubber molecules may develop a cross-linked network structure at high temperatures by adding chemical reagents like sulfur, which significantly enhances the material’s mechanical and heat-resistant qualities, among other qualities.
To have the greatest vulcanization result, the vulcanization process has to have control over process variables including temperature, pressure, and time. Vulcanization methods will vary depending on the product.
3.5 Post-processing process (such as cutting, surface treatment, etc.)
Surface treatment, cutting, and other post-processing procedures are the final steps in the manufacturing of rubber goods. The product is given the appropriate size, look, and other qualities via the employment of these procedures.
Performance and ultimate product quality are also impacted by the choice and management of post-processing procedures. For instance, rubber goods’ chemical and wear resistance may be increased using surface treatment technologies.
4. The impact of production technology on rubber properties
4.1 Impact of formulation design on performance
The ultimate performance of rubber goods is directly influenced by their formula design. Rubber may be made to have the necessary mechanical, thermal, and chemical resistance qualities using a suitable formula.
4.2 Selection and proportion of various raw materials in the formula
The most important factors are the kind and quantity of rubber base material. Among the often utilized types are nitrile rubber, styrene-butadiene rubber, natural rubber, and others, each with unique performance attributes.
The kind and quantity of additions will have a big impact on performance as well. For instance, the strength is influenced by the amount of filler and the degree of vulcanization is determined by the amount of sulfur.
4.3 Types and dosage of additives
Performance will also be significantly impacted by other ingredients in the mix, such as sulfur, accelerators, antioxidants, fillers, etc., in addition to the rubber base material. Appropriate choice and management of additive type and dosage are essential.
4.4 Effect of mixing process on performance
Basic characteristics of rubber compounds, such their flexibility and fluidity, are determined by the mixing process. Thermal deterioration will result from a mixing temperature that is too high, and molecular weight will decrease from a mixing period that is too lengthy.
4.5 Mixing temperature, time, rotation speed and other parameters
The performance of the finished product is directly impacted by the regulation of process variables like temperature, time, and rotation speed during mixing.
4.6 Selection of mixing equipment
The performance of various mixing equipment types, such as open mixers and internal mixers, will vary depending on the mixing effects produced.
4.7 Impact of molding process on performance
The performance of the product will also be significantly impacted by the choice and management of the molding process. For instance, extrusion molding works well for pipes, films, and other materials, but injection molding may create parts with intricate geometries.
4.8 Characteristics and application scope of different molding methods
Every molding method has its own unique properties and range of uses. For instance, extrusion is better suited for continuous production of pipes, films, etc., whereas injection molding works well for producing intricate components.
4.9 Effect of molding parameters on product performance
The final product’s mechanical qualities, surface quality, and dimensional accuracy depend heavily on the precise control of factors like temperature, pressure, and flow rate throughout the molding process.
4.10 Effect of vulcanization process on performance
A crucial stage in the creation of rubber goods is vulcanization. The final product’s mechanical qualities, heat resistance, chemical resistance, and other characteristics are directly determined by the choice and management of the vulcanization process.
4.11 Vulcanization temperature, time, pressure and other parameters
The vulcanization effect and subsequent impact on product performance depend on the accurate regulation of vulcanization temperature, duration, pressure, and other variables.
4.12 Characteristics of different vulcanization systems
Apart from traditional sulfur vulcanization, there exist many other vulcanization methods, such peroxide vulcanization and no vulcanization, that have their own unique properties and are appropriate for distinct materials.
5. Case analysis and discussion
5.1 The production process and performance characteristics of a specific rubber product
For study, let’s use a specific kind of tire rubber for automobiles. Good wear resistance, low rolling resistance, and tear resistance are requirements for this tire material.
Its manufacturing procedure mostly consists of:
- Formula design: Add silicone, carbon black, antioxidants, and styrene-butadiene rubber in the same proportions as natural rubber.
- Process of mixing: using an internal mixer to mix at high temperatures and high shear while regulating time and temperature.
- Molding procedure: Tread rubber is made in thin layers using the calendering molding procedure.
- Vulcanization procedure: The vulcanizer is used for 15 to 20 minutes to accomplish high-temperature and high-pressure vulcanization.
Products made of tire rubber with low rolling resistance, high wear resistance, and tear resistance can be produced using this production method.
5.2 Production process optimization improves product performance
Product performance may be further enhanced by further refining the production method mentioned above:
- To improve tear resistance, optimize the formula by adding more highly crystalline styrene-butadiene rubber.
- Optimization of mixing: raise the temperature and duration of mixing, raise the density of dispersion and cross-linking, and raise wear resistance.
- Forming optimization: To increase the homogeneity of thin-layer tire materials, optimize calendering parameters like temperature, pressure, etc.
- Optimize vulcanization by increasing the vulcanization duration, raising the temperature properly, and enhancing heat resistance and cross-linking density.
5.3 Application of emerging process technologies in the production of rubber products
A few newly developed procedures are being used in the manufacturing of rubber goods as a result of technological advancements:
- Thermoplastic rubber (TPV) technology: By blending thermoplastics with rubber, TPV combines the benefits of both materials.
- Dynamic vulcanization technology: By carrying out the vulcanization reaction concurrently with the mixing process, manufacturing costs may be minimized.
- Spray molding technology: Rubber items are made using this procedure, which works well for producing intricate parts.
- 3D printing technique: Create small-batch or sample rubber items with 3D printing technology.
